Sam Neill, Laura Dern and Jeff Goldblum will reprise their roles in the upcoming Jurassic World 3.
The actors led the cast of the 1993 hit, directed by Steven Spielberg, and have appeared separately in subsequent instalments.
Dern confirmed she was "so excited" to rejoin her "friends" at a Los Angeles screening of Jurassic World on Tuesday.
Afterwards she added: "Loved joining my buddy, Colin [Trevorrow, director], to announce the return of the original cast of Jurassic Park back into the Jurassic World."
It is believed the trio will appear alongside Chris Pratt and Bryce Dallas Howard, the stars of 2015's Jurassic World and 2018's Jurassic World: Fallen Kingdom.
The latter release saw Goldblum reprise his role as Dr Ian Malcolm, having previously done so in 1997's The Lost World: Jurassic Park.
Neill and Dern reprised their roles as Dr Alan Grant and Dr Ellie Sattler in 2001 film Jurassic Park III.
In recent years Neill has been seen as Chester Campbell in Peaky Blinders, while Goldblum released an album of jazz tunes in 2018.
Old and new
The original Jurassic Park film was adapted from the novel by Michael Crichton.
It became one of the highest-grossing films of all time and won three Oscars.
Reese Witherspoon, who acted alongside Dern in 2014 film Wild and TV series Big Little Lies, shared her excitement at the news.
She wrote on Twitter: "I love every Jurassic World movie but now THIS?!?"
The next addition to the series, due out in 2021, will be the sixth Jurassic film in total.